1. Field
One or more embodiments relate to a field emission device and a method of manufacturing the same.
2. Description of the Related Art
Field emission devices emit electrons from emitters formed on cathodes by forming a strong electric field around the emitters. Field emission devices may be applied to field emission displays (“FEDs”), which display images by the collision of electrons emitted from a field emission device with a phosphor layer formed on anodes, backlight units (“BLUs”) of liquid crystal displays (“LCDs”), and the like. LCDs display images on a front surface by passing light, which may be generated by a light source installed on a rear surface, through a liquid crystal, which controls light transmittance. Examples of the light source installed on the rear surface of the LCDs may include a cold cathode fluorescence lamp (“CCFL”) BLU, a white light emitting diode (“WLED”) BLU and a field emission BLU. The CCFL BLU provides desirable color reproducibility and can be manufactured at low cost. However, since the CCFL BLU uses Hg, the CCFL BLU may pollute the environment, and because the CCFL BLU may not be dynamically controlled the CCFL BLU may not increase brightness and contrast. The WLED BLU can be dynamically controlled, but incurs high manufacturing costs and has a complicated structure. The field emission BLU can be locally dimmed and impulse/scan-driven to thereby maximize brightness, contrast and the quality of motion pictures. Thus, a field emission BLU having low manufacturing cost is desirable for use as a next-generation BLU. The field emission devices may also be applied to other various systems using electron emission, such as X-ray tubes, microwave amplifiers and flat lamps.
Micro tips formed of a metal such as molybdenum (Mo) have been used as emitters in field emission devices. Also, in some commercial field emission devices, carbon nanotubes (“CNTs”), which provide good electron emission, are used as emitters. Field emission devices using CNT emitters are low-priced, are driven with a low voltage and have good chemical and mechanical stability.
Commercially available field emission devices are currently manufactured by performing photo patterning and firing several times, thus their manufacture is complicated and expensive. More specifically, metal electrodes, such as cathodes, may be roughly formed in two ways. In a first way, Cr, Mo or the like is deposited by vacuum deposition and then patterned by photolithography. In a second way, Ag or the like is stencil-printed and then fired. However, the first way requires vacuum deposition equipment and is complicated, and in the second way an expensive material is used, thus the resulting field emission devices are manufactured at high cost. Accordingly, there remains a need in the art for a lower cost field emission device.